Forms for poured concrete manholes typically include steel shell outer forms and steel shell inner forms, both of which are designed to be disassembled and reused. Inner forms originally designed for new poured concrete manholes have also been used by themselves to cast concrete liners for the renewal of old, existing manholes, but the forms and methods used for producing new cast-in-place manholes in many instances are not adaptable for casting liners in existing, deteriorating manholes.